id:A072530 - OEIS Search Results

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Number of primes p such that n divided by p leaves a prime remainder.

+0
8

0, 0, 0, 0, 1, 0, 1, 2, 1, 1, 1, 2, 2, 2, 1, 3, 3, 3, 2, 3, 1, 3, 3, 5, 2, 4, 2, 4, 3, 4, 3, 4, 4, 3, 2, 6, 4, 5, 2, 6, 4, 6, 3, 6, 4, 5, 5, 7, 4, 6, 4, 5, 4, 8, 3, 5, 4, 7, 5, 9, 3, 7, 5, 8, 5, 7, 3, 8, 4, 8, 5, 10, 6, 7, 5, 8, 4, 9, 6, 9, 7, 8, 4, 10, 5, 7, 6, 8, 7, 12, 5, 8, 8, 8, 5, 12, 6, 10, 5, 10, 5 (list; graph; listen)

	OFFSET	`1,8`
	COMMENT	`Is there any n > 6 such that a(n) =0 ?`
	EXAMPLE	`a(17) = 3: there are 3 primes viz. 3, 5 and 7 which leave prime remainders on dividing 17.`
	MATHEMATICA	`Table[Count[PrimeQ[Table[Mod[w, Prime[j]], {j, 1, PrimePi[w]}]], True], {w, 1, 256}]`
	CROSSREFS	`Cf. A072531.` `Sequence in context: A087048 A109700 A087742 this_sequence A090455 A086288 A104360` `Adjacent sequences: A072527 A072528 A072529 this_sequence A072531 A072532 A072533`
	KEYWORD	`nonn`
	AUTHOR	`Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Aug 01 2002`
	EXTENSIONS	`More terms from Labos E. (labos(AT)ana.sote.hu), Aug 02 2002`

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Last modified December 19 12:50 EST 2009. Contains 171053 sequences.

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